1. Field of the Invention
The present invention relates to an electrophotographic image forming apparatus. More particularly, the present invention relates to an electrophotographic image forming apparatus including a developing roller which uses a non-magnetic mono-component toner and a developing method using the same.
2. Description of the Related Art
An electrophotographic image forming apparatus using non-magnetic mono-component toner includes a regulating blade for regulating the thickness of a toner layer formed on a developing roller. The regulating blade can be divided into a variety of types according to the installation direction of the regulating blade. For example, the regulating blade can be installed such that the direction of the leading end portion of the regulating blade is the same as a direction opposite to the rotational direction of a developing roller. This is typically referred to as a counter type or leading type regulation blade. This type of regulating blade helps to maintain a uniform toner layer on the developing roller. However, the regulating blade is disadvantageous in that minimizing the size of the developing unit is relatively difficult. In another type of regulating blade, namely the trail type regulating blade, the leading end portion of the regulating blade is installed in the same direction as the rotational direction of the developing roller. This type of regulating blade is advantageous in minimizing the size of the developing unit. However, the regulating blade requires a greater contact force with the developing roller because the regulating blade can be pushed by the toner. Thus, a toner filming phenomenon can be generate due to higher contact forces. Also, the life span of the developing unit may be reduced.
Accordingly, there is a need for an electrophotographic image forming apparatus adopting a trail type regulating blade which enables reduction in the size of the apparatus and an improved life span of the developing unit.